U.S. patent number 4,255,766 [Application Number 06/056,287] was granted by the patent office on 1981-03-10 for facsimile signal superposing system.
This patent grant is currently assigned to Nippon Telegrpah and Telephone Public Corporation. Invention is credited to Takaaki Adachi, Kenichi Hanabe, Takashi Kawade, Hideo Matsuda, Kiyohiro Yuki.
United States Patent |
4,255,766 |
Matsuda , et al. |
March 10, 1981 |
Facsimile signal superposing system
Abstract
A facsimile signal superposing system for an analog type
modulated facsimile signal has been found. The present superposing
system has a digital memory storing the pattern to be superposed,
and the insertion circuit which has a first input terminal for
receiving the original facsimile pattern, a second input terminal
for receiving the output of said digital memory, and an output
terminal providing the sum of the first and the second input
terminal signals. The cells of the digital memory are read one
after another substantially synchronized with the original picture
signal, thus, a superposed facsimile signal is obtained at said
output terminal. The additional pattern to be superposed is, for
instance, the date of the facsimile transmission.
Inventors: |
Matsuda; Hideo (Yokosuka,
JP), Yuki; Kiyohiro (Yokosuka, JP), Kawade;
Takashi (Yokosuka, JP), Adachi; Takaaki
(Yokosuka, JP), Hanabe; Kenichi (Yokohama,
JP) |
Assignee: |
Nippon Telegrpah and Telephone
Public Corporation (Toyko, JP)
|
Family
ID: |
27466759 |
Appl.
No.: |
06/056,287 |
Filed: |
July 10, 1979 |
Foreign Application Priority Data
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Jul 10, 1978 [JP] |
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53-82926 |
Jul 10, 1978 [JP] |
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53-82927 |
Aug 14, 1978 [JP] |
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53-98814 |
Aug 14, 1978 [JP] |
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53-98815 |
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Current U.S.
Class: |
358/435;
348/564 |
Current CPC
Class: |
H04N
1/32133 (20130101); H04N 1/3871 (20130101); H04N
2201/3274 (20130101); H04N 2201/3271 (20130101); H04N
2201/3214 (20130101) |
Current International
Class: |
H04N
1/32 (20060101); H04N 1/387 (20060101); H04N
001/32 (); H04N 003/22 () |
Field of
Search: |
;358/93,183,256,257,258 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Bookbinder; Marc E.
Assistant Examiner: Coles; Edward L.
Attorney, Agent or Firm: Armstrong, Nikaido, Marmelstein
& Kubovcik
Claims
What is claimed is:
1. A facsimile superposing system for superposing an additional
pattern on an original pattern comprising an input means for
receiving the analog type original facsimile pattern signal
modulated by either the AM, AM-PM, FM, or PM systems, a digital
memory having the capacity enough to store the additional pattern
to be superposed, an insertion circuit having a first input
terminal connected to said input means, a second input terminal
connected to the output of said digital memory and an output
terminal for providing the sum of the first and the second input
terminal signals, a write circuit connected to said digital memory
for writing a desired pattern into the memory, an address circuit
including a cell counter and a line counter both connected to said
memory for addressing said digital memory, said cell counter having
the capacity equal to the number of cells in a single scanning line
of the original pattern and the line counter having the capacity
enough to count the number of scanning lines of the additional
pattern, a cell clock generator to increment said cell counter and
the frequency of which is equal to the scanning frequency of the
original pattern, said line counter being incremented by the
overflow pulse of said cell counter, and output means connected to
the output terminal of said insertion circuit.
2. A facsimile superposing system according to claim 1, further
comprising means for initiating said address circuit when a
confirmation receive signal from the reception side is
detected.
3. A facsimile superposing system according to claim 1, wherein
said insertion circuit has means for suppressing the amplitude of
the signal at the first input terminal according to the signal at
the second input terminal, and the original facsimile pattern is
modulated by the AM or AM-PM systems.
4. A facsimile superposing system according to claim 1, wherein
said insertion circuit has an oscillator for providing the picture
frequency, the first input terminal and the output of said
oscillator are alternatively connected substantially according to
the signal at the second input terminal, and the original facsimile
pattern is modulated by the AM, FM, or AM-PM systems.
5. A facsimile superposing system according to claim 1, wherein
said insertion circuit has means for inverting the phase of the
first input terminal signal according to the signal at the second
input terminal, and the original facsimile pattern is modulated by
the AM-PM or PM systems.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a system to superpose a picture
and/or a character pattern on an original facsimile pattern which
is in the modulated analog signal form of amplitude modulation
(AM), amplitude-phase modulation (AM-PM), frequency modulation (FM)
and/or phase modulation (PM).
In a facsimile transmission system and/or a facsimile exchange
system, superposition of an additional pattern on the original
facsimile pattern is sometimes required. That additional pattern
is, for instance, the date and/or the time that the facsimile
signal is transmitted, calling subscriber recognition information,
charge information, or other comments for communication
purposes.
According to a prior apparatus of this kind, a modulated facsimile
signal is temporarily received by a facsimile receiver, and the
baseband signal in the analog form thus obtained is converted to a
digital form through digital sampling process. Then the facsimile
signal in the digital form thus obtained is added logically to a
character signal in the digital form obtained from the control
apparatus for character generation, and then the resultant logical
sum is transmitted through a facsimile transmitter.
However, said prior facsimile superposition system has the
disadvantages that a facsimile transmittes is necessary, thus the
system structure is complicated, and further a picture quality is
deteriorated since a facsimile signal is converted to a baseband
signal for digital sampling.
SUMMARY OF THE INVENTION
It is an object, therefore, of the present invention to overcome
the disadvantages and limitations of a prior facsimile superposing
system by providing a new and improved facsimile superposing
system.
It is also an object of the present invention to provide a
facsimile superposing system in which an additional pattern is
superposed on an original pattern without demodulating the original
facsimile signal. That is to say, the analog type facsimile signal
modulated by amplitude modulation, amplitude-phase modulation,
frequency modulation, and/or phase modulation is directly
superposed with an additional pattern.
The above and other objects are attained by a facsimile superposing
system for superposing an additional pattern on an original pattern
comprising an input means for receiving the analog type modulated
original facsimile pattern signal, a digital memory storing the
additional pattern to be superposed, an insertion circuit having a
first input terminal connected to said input means, a second input
terminal connected to the output of said digital memory and an
output terminal for providing the sum of the first and the second
input terminal signals, an address circuit for addressing said
memory, and output means connected to said output terminal of said
insertion circuit.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing and other objects, features, and attendant advantages
of the present invention will be understood by means of the
following description and accompanying drawings wherein;
FIG. 1 shows the general block-diagram of the facsimile exchange
system according to the present invention,
FIG. 2 shows the transmission control procedure of a typical
facsimile transmission system,
FIG. 3 shows the block-diagram of the embodiment of the facsimile
superposing apparatus according to the present invention,
FIG. 4 shows the operational timing sequence of the apparatus in
FIG. 3,
FIGS. 5(A), 5(B) and 5(C) are some embodiments of the insertion
circuit 30 in FIG. 3,
FIGS. 6, 7 and 8 are waveforms of the insertion circuits in FIGS.
5(A), 5(B) and 5(C), respectively,
FIG. 9(A) and FIG. 9(B) are modifications of the insertion circuit,
and
FIG. 10 is the simplified modification of the apparatus in FIG.
3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows the general block-diagram of a facsimile exchange
system utilizing the present invention, in which the reference
numeral 1 is the facsimile transmitter, 2 is the modulator for
modulating the facsimile base band signal from the facsimile
transmitter 1 by AM (amplitude modulation), AM-PM (amplitude-phase
modulation), FM (frequency modulation), or PM (phase modulation). 3
is the facsimile exchange apparatus and/or the facsimile repeater,
4 is the demodulator for recovering the facsimile base band signal
from the modulated signal, and 5 is the facsimile receiver. Also,
10 is the facsimile superposing apparatus inserted in the
transmission line between the output of the modulator 2 and input
of the demodulator 4. Supposing that the original pattern at the
facsimile transmitter 1 is the pattern (A) and the additional
pattern to be superposed at the facsimile superposing apparatus is
the pattern (B), then the superposed pattern at the facsimile
receiver 5 is the pattern (C), which is the summation of the
pattern (A) and the pattern (B). The present invention relates to
superposing a pattern as described. It should be understood in FIG.
1, that the facsimile signal is not processed through a complicated
digital information processing technique, but is transmitted in a
simple analog form and is superposed with an additional
pattern.
FIG. 2 shows the transmission control procedure of a typical
facsimile transmission system according to recommendation T30 of
CCITT (International Telegraph and Telephone Consultive Committee
which is a subsidiary organization of the United Nations). In FIG.
2, the facsimile transmitter (FAX-S) forwards the phasing signal
(PHS) which is the repetition of the O-phase signal and the
.pi.-phase signal for synchronization between the transmission side
and the reception side. Said O-phase signal and the .pi.-phase
signal are 2,100.+-.10 Hz in said recommendation with a duration of
less than 6 seconds, and the beginning point of either O-phase
signal or .pi.-phase signal is the reference point of the
synchronization. When the reception side assures that reference
point and synchronization is established between two stations, the
reception side returns the "confirmation to receive" signal (CFR)
which is 1080 Hz and continues for 3 seconds .+-.3%. When the
transmission side receives the CFR signal, the transmission side
recognizes that the reception side is ready to receive a picture
and synchronization has been established, so the transmission side
starts to forward a picture signal (PIX). When the transmission
side finishes forwarding the picture signal, the EOM (end of
message) signal is forwarded from the transmission side to the
reception side, and the MCF (message confirmation) signal is
returned from the reception side to the transmission side. Thus,
when the transmission side receives the MCF signal, the sequence of
facsimile transmission procedures finishes.
Accordingly, the facsimile superposing apparatus 10 according to
the present invention must operate in coincidence with said
facsimile transmission procedure.
FIG. 3 shows the block-diagram of the embodiment of the facsimile
superposing apparatus according to the present invention. In the
figure, the reference numerals 12 and 12a are hybrid circuits for
converting the two-wire system to a four-wire system or a four-wire
system to a two-wire system. The two-wire end of the first hybrid
circuit 12 is connected to the facsimile transmitter through the
transmission circuit and the modulator, and the two-wire end of the
other hybrid circuit 12a is connected to the facsimile receiver
through the transmission circuit and the demodulator. 14 is the
detector/demodulator, 16 is the digital cell counter which has a
bit capacity equal to the number of picture cells in each scanning
line of a facsimile picture. 18 is a line counter which has a bit
capacity equal to the cells in the vertical direction of a
facsimile picture, and is incremented by an overflow pulse of said
cell counter 16. 20 is the digital memory for storing the pattern
to be superposed (see the symbol (B) in FIG. 1), and said memory is
a read-only-memory (ROM) or a random access memory (RAM). The
address for reading out said memory is determined by the outputs of
said cell counter 16 and the line counter 18. 22 is the
memory-write circuit for changing the content of the memory. The
change of content of the memory is performed when the pattern to be
superposed must be changed, for instance, when the pattern to be
superposed is a date, that date must be changed every day. 24 is
the CFR detector, 26 is the AND circuit, 28 is the cell clock
generator which generates a frequency signal equal to the scanning
frequency of the picture signal, and 30 is the signal insertion
circuit which superposes the additional pattern from the second
input terminal of the line (q) on the original pattern of the first
input terminal of the line (p), thus the superposed pattern is
provided at the output terminal on the line (r). The structure of
the insertion circuit depends upon the modulation system of the
facsimile system (AM, AM-PM, FM, or PM), and will be described
later.
At the initial status, it is supposed that the output of the CFR
detector 24 is "low", then the AND circuit 26 is open, and the line
counter 18 is cleared through the CR terminal. Then the output (q)
of the memory 20 is "low" level. It is assumed that the input
terminal (p) is directly connected to the output terminal (r) of
the insertion circuit when the output (q) of the memory 20 is
"low", and when said output (q) of the memory 20 is "high", the
output (q) of said memory 20 is applied to the output (r) of the
insertion circuit 30. The cell counter 16 is cleared through the
terminal CR every time the synchronization signal from a facsimile
transmitter is provided at the output of the detector/demodulator
14 until the CFR signal is detected. Then the content of the cell
counter 16 is incremented by the output of the cell clock generator
28 and said content reaches full (for instance, 1728) when next
synchronization signal appears on the output of the
detector/demodulator 14.
FIG. 4 (in particular the left half of FIG. 4) shows the sequence
of the above operation, in which (a) is the output of the
detector/demodulator 14 which provides the synchronization signal
(S), (b) is the output of the CFR detector 24, (c) is the output of
the cell counter 16, (d) is the output of the line counter 18, and
(e) is the output of the memory 20.
Accordingly, it should be understood that when no CFR signal is
detected, the first hybrid circuit 12 is directly connected to the
second hybrid circuit 12a through the insertion circuit 30, thus
the superposition apparatus in FIG. 3 does not affect to the
transmission line. Therefore, the PHS signal (FIG. 2) can go
through the apparatus freely.
Next, when a facsimile receiver returns the CFR signal, said signal
is detected by the CFR detector 24 at the time (T) in FIG. 4, then
the output of the CFR detector changes to "high" level (see FIG.
4(b)). Thus, the line counter 18 and the cell counter 16 are not
cleared, instead, the content of the cell counter 16 and the line
counter 18 indicate the address of the cell which corresponds to
the instantaneous scanning signal of the facsimile signal.
According to the address thus indicated, the memory 20 provides the
output signal which is applied to the insertion circuit 30 and the
pattern from the memory 20 is superposed on the original
pattern.
Now, the structure and the operation of the insertion circuit 30
will be described.
In FIGS. 5(A), 5(B) and 5(C), OP shows an operational amplifier,
R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are resistors, FET,
FET.sub.1 and FET.sub.2 are field effect transistors, and the
terminals p, q and r correspond to the same symbols of the
insertion circuit in FIG. 3.
FIG. 5(A) is the first embodiment of the insertion circuit which is
utilized for AM (amplitude modulation), or AM-PM (amplitude-phase
modulation) modulated facsimile signals. In FIG. 5(A), when the
level at the terminal (q) is "low", the FET is cut off and the
input terminal (p) is directly connected to the output terminal (r)
through the operational amplifier, thus, the AM waveform of the
facsimile signal (see FIG. 6(a)) is directly output to the terminal
(r). On the other hand, when the terminal (q) is in the "high"
state (see FIG. 6(b)), then the FET conducts and the terminal (p)
is grounded through said field effect transistor FET. Therefore,
the input signal at the terminal (p) does not appear at the output
terminal. Thus, the amplitude of the input signal is suppressed.
The suppression of the input signal causes the picture signal to
change from white to black. In the waveforms in FIG. 6, the
waveform (a) is the AM modulated facsimile signal, (a') is the base
band signal of the waveform (a), (b) is the additional signal to be
inserted on the terminal (q), (c) is the superposed output signal
on the terminal (r) and (c') is the base band signal of the
waveform (c). In those drawings, it should be understood that the
picture signals b.sub.4 and b.sub.6 are suppressed.
FIG. 5(B) is the second embodiment of the insertion circuit in FIG.
3, and is utilized for AM, AM-PM or FM modulated facsimile signals.
In FIG. 5(B), according to the level on the insertion terminal (q),
the field effect transistors FET.sub.1 and FET.sub.2 are cut off or
conductive. When the first field effect transistor FET.sub.1 is
conductive, the output of the oscillator is grounded, and when the
second field effect transistor FET.sub.2 is conductive the terminal
(p) is grounded. Of course the grounded signal does not appear on
the output terminal (r). Therefore, according to the level at the
terminal (q), either the input terminal (p) or the output of the
oscillator OSC is connected to the output terminal (r) through the
operational amplifier OP. The frequency of the oscillator OSC is
the same as that of the picture signal in the AM or AM-PM systems,
or said frequency is the same as the black frequency or the white
frequency in the FM system.
FIG. 7 shows the operational waveforms of the circuit in FIG. 5(B),
and (a) shows the input waveform at the input terminal (p), (a') is
the base band signal of the waveform (a), (b) is the additional
signal at the terminal (q), (c) is the superposed output signal at
the output terminal (r), and (c') is the base band signal of the
waveform (c). It should be understood in FIG. 7, that the signals
are superposed at the cells b.sub.3 and b.sub.6.
FIG. 5(C) is the third embodiment of the insertion circuit
according to the present invention, and this embodiment is utilized
for AM-PM, or PM modulated facsimile signals. In FIG. 5(C), the
input signal applied to the negative terminal (-) of the
operational amplifier OP, is inverted while the signal applied to
the positive terminal (+) of the operational amplifier OP is not
inverted in the operational amplifier. Therefore, by designing the
value of the resistance of R.sub.1, R.sub.2 and R.sub.3
appropriately, the inverted signal is obtained when the FET is
conductive, while the non-inverted signal is obtained when the FET
is cutoff. Thus, the signal at the insertion terminal (q) can
control the phase at the output terminal (r).
FIG. 8 shows the operational waveforms of the circuit in FIG. 5(C),
when that circuit is applied to AM-PM modulated facsimile signals.
In FIG. 8, (a) shows the input AM-PM facsimile signal, (a') is the
base band signal of the waveform (a), (c) is the superposed output
signal at the output terminal (r), and (c') is the base band signal
of the waveform (c). It should be understood that the output signal
on the waveform (c) is inverted at the timing b.sub.3, b.sub.4 and
b.sub.9. Therefore, the demodulated signal (waveform (c')) has a
thin spot of black signal B at the timing b.sub.3, b.sub.4 and
b.sub.9. Thus, an additional pattern is inserted as a black spot in
an original picture.
Next, some modifications of the present facsimile superposing
system will be described.
FIG. 9(A) and FIG. 9(B) are two alternatives of the insertion
circuit in FIG. 5(A). In FIG. 9(A), the photo-coupler PC is
controlled to be either conductive or cut off by the insertion
signal at the terminal (q) through the driver transistor Tr. Then,
when the photo-coupler is cut off the input facsimile signal is
suppressed. In FIG. 9(B), the complementary
metal-oxide-semiconductor C-MOS is controlled to be conductive or
cutoff by the insertion signal at the terminal (q), and of course
when that C-MOS is cutoff, the facsimile signal is suppressed.
It should be understood that many other modification of the
insertion circuit, are possible to those skilled in the art as long
as that insertion circuit can be switched by the insertion
signal.
FIG. 10 is a modification of the facsimile superposing apparatus,
and the same reference numerals as those in FIG. 3 show the same
members. In FIG. 10, means for clearing or initializing the cell
counter 16 and the line counter 18 are omitted. Therefore, the
additional pattern is superposed in an out-of synchronization
condition, although the line repetition rate is the same, and the
superposed pattern will be divided into an upper portion and lower
portion, or a left portion and right portion. However, if the
pattern to be superposed has many repetitions of the same string of
characters, the superposed pattern is readable somewhere on the
received copy. So, FIG. 10 provides a simplification of the
facsimile superposing apparatus.
Further, it should be understood that the present facsimile
superposing apparatus can be inserted not only in the repeater or
the exchange system, but also in the facsimile transmitter or
receiver, or an attachment of the facsimile transmitter or
receiver.
As mentioned above, according to the present invention, the
superposing of the desired pattern is performed with a simple
apparatus without demodulating the facsimile signal to the base
band signal. Therefore, the superposing is performed without
deteriorating the picture quality.
From the foregoing it will now be apparent that a new and improved
facsimile superposing system has been found. It should be
understood of course that the embodiments disclosed are merely
illustrative and are not intended to limit the scope of the
invention. Reference should be made to the appended claims,
therefore, rather than the specification as indicating the scope of
the invention.
* * * * *